SE537216C2 - Air duct for vehicles and a method for manufacturing an air duct - Google Patents

Abstract

An air duct pipe (2) for an internal combustion engine, in particular for a motor vehicle, consisting of at least two rudder parts (4, 6) which are made of a plastic material by injection molding and which are connected to each other along an interconnection line (8) formed by an interconnection duct (10) formed by connecting parts (12, 14) for the respective rudder part in the area of the connecting line (8). The rudder parts (4, 6) are connected to each other and the joints are joined to each other by injecting said plastic material into said connecting channel (10). The connecting parts (12, 14) comprise internal connecting parts (16, 18) which are designed so as to form a smooth connecting surface (20) on the inside of the air duct tube (2) and which are adapted to absorb pressure from the connecting duct (10) during the injection of said plastic material in the interconnection duct. Said connecting parts (12, 14) comprise outer connecting parts (22, 24) which are adapted to mechanically keep the rudder parts connected.

Description

537 216 Title Air duct for vehicles and a method for manufacturing an air duct.

FIELD OF THE INVENTION The present invention relates to an air duct pipe and a method of manufacturing an air duct pipe, for a vehicle, according to the preambles of the independent claims.

Background to the invention The automotive industry is constantly working to improve the industry economy for the vehicle while at the same time meeting more stringent environmental requirements. This also entails a constant effort to reduce the costs of the components, but at the same time to maintain or increase the quality of these. Today, air duct pipes for clean air are manufactured from a filter to the inlet for the compressor (turbo) either as blow-molded parts of plastic, cast rubber parts or sometimes even of metal. The geometry of these channels is often complicated, which means that injection molding of plastic parts has not been relevant so far.

For other manufacturing processes, in addition to injection molding, some finishing of the parts must be done because there is often a risk that chips and burrs may appear in the finished product and that the surfaces become coarser than what is undesirable.

An example of a manufacturing process is blow molding, which is one of the most common methods for manufacturing thermoplastic hollow body articles.

Another manufacturing process is injection molding. Injection molding is a common manufacturing method, especially for details of various thermoplastics.

Injection molding is most suitable for articles that are not slippery bodies or only in special cases for tubular parts.

For air duct pipes on the clean-air side, there are strong wishes that the pipes must have smooth inner surfaces, have low weight, have a geometry that has controllable details, for example rock thicknesses, and have two curve shapes, ie. the rudder has curve shapes in three dimensions.

Traditionally, blow molding has been the first choice in the manufacture of such pipes, but due to the variations in the cross section and the complex curve shape, the machining of the parts will result in high costs and also in responsibilities to maintain high quality in the manufacture.

The oval opening located upstream of the air duct pipe means that there is a need for a robotic machining of the inner surface in the opening. Even if it were possible to loosen, variations in the cradle thickness would still occur and it would not be possible to gradually insert details on the inside, for example guide rails to control the air flow.

A disadvantage of the air duct tubes used today is that it is complicated to manufacture an air duct tube with sufficiently high quality as it depends on the purity, weight and geometric shape of such a duct. In addition, the duct can have several bending angles, which further complicates the manufacture.

In view of these drawbacks, the inventor has realized that these can be eliminated by providing an air duct pipe consisting of at least two injection molded parts which are joined together. Darigenonn achieved, among other things, an improved manufacturing process.

A similar manufacturing process is described in US-2010/0192891. This patent document describes an air manufacturing process for an air duct pipe, for example for an internal combustion engine. The pipe consists of at least two injection molded parts. In order to be able to join these parts, a suitable material is supplied by casting or injection into the surface (joint) between these two parts. In more detail, the joint consists of a U-shaped part which runs along the edge of one injection-molded part and which forms a channel when it abuts against a straight part of the other injection-molded part. 2 537 216 A suitable material is then injected into the formed channel to join the parts together.

The object of the present invention is to provide an improved air duct pipe, and an improved method for manufacturing such an air duct pipe, with respect to the quality of the assembly of the integral pipe parts. Among other things, to ensure that a smooth surface is obtained on the inside of the pipe and that the joining channel can be filled with plastic material under high pressure to ensure that the joint is sealed.

Summary of the Invention The above objects are achieved by the invention defined by the independent claims.

Preferred embodiments are defined by the dependent claims.

According to the present invention, injection molding is used of at least two pipe parts which are interconnected to form the air duct pipe. In the true connection line, an interconnection channel is created where the same plastic material as for the rudder parts is injected to create a tight joint between the rudder parts.

In order to facilitate control of the pre-spraying, a so-called hot channel forming system is preferably used.

The advantage of using injection molding is that this is a process that gives a better accuracy regarding the dimensions, for example of the rock thicknesses, compared to other processes, which has been discussed above. It is clean and, as in one embodiment, injecting a tat that instead of having to use expensive welding equipment results in a lower manufacturing cost. Welding of articles with double-curved surfaces is complex even from the perspective of containing tightness and geometry requirements. The method according to the invention involved a fast manufacturing process for the air duct tube. As an example of manufacturing time, it can be mentioned that a finished tube can be manufactured in less than 200 seconds, and preferably less than 150 seconds.

According to the invention, the rudder parts are injection molded simultaneously in two different injection molds with cavities corresponding to the respective part. The injection molds are designed so that for each of the pipe parts a part of an interconnecting channel is formed along the edges of the pipe parts which are to be joined to the finished air duct pipe.

The pre-sprayed pipe parts are taken out of their molds and placed in a third mold with a cavity corresponding to the finished air duct pipe.

The parts are mechanically joined by the respective connecting part being forced into engagement with each other.

An interconnection channel, ie. a cavity, is formed by the mechanically interconnected connecting parts.

According to one embodiment, the connecting part on one of the pipe parts is designed so that a clamping force can be applied to hold the parts in place.

Preferably, guiding surfaces are arranged on each part to guide the parts in relation to each other so that the inner surface of each rudder ends up in the same plane so that the joint is beaten on the inside. The connecting parts also function as the counter cla joining duct is filled with the same plastic material (a thermoplastic).

Finally, the joining channel is filled with the same plastic material as the rudder parts themselves.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of an air duct pipe according to the present invention. 4 537 216 Figure 2 is a cross-section showing the interconnection between the rudder parts according to a first embodiment of the invention.

Figure 3 is a cross-sectional view showing the connection between the pipe parts according to a second embodiment of the invention.

Figure 4 is a flow chart illustrating the method of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION In the figures, the same or similar details are denoted by the same reference numerals.

The invention will now be described in detail with reference to the figures. In the description of the air duct pipe, reference will be made to Figures 1-3.

Figure 1 shows a schematic view of an air duct 2 according to the invention. The rudder is intended to be used for an internal combustion engine, for example in a motor vehicle, in a work machine or in a ship, and is preferably adapted to be arranged so that for clean air there is a filter to the inlet of a compressor adjacent to the engine turbocharger.

The air duct pipe has two openings 3, 5. The oval opening 5 is located upstream of the air duct pipe. The second opening 3 is preferably circular. The flow direction is indicated in the figure by an arrow.

According to the invention, the air duct pipe 2 comprises at least two pipe parts 4, 6 which are made of a plastic material by injection molding.

Figures 2 and 3 show how these rudder parts are connected to each other along an interconnection line 8 which consists of an interconnection channel 10 formed by interconnection parts 12, 14 for each rudder part in the area of the interconnection line 8. More specifically, the interconnection channel 10 is formed by a cavity formed in facing parts of the connecting parts 12, 14 where the boundary cradles for the halo ring form 537 216 of inner surfaces of the connecting parts 12, 14. When the pipe parts are mechanically connected to each other, the connecting channel forms a closed channel where an injection opening is provided. the rudder parts 4, 6 are joined together.

The connecting parts 12, 14 further comprise inner connecting parts 16, 18 which are designed so as to form a smooth connecting surface 20 on the inside of the air duct 2.

The inner connecting parts 16, 18 are further adapted to absorb pressure from the connecting channel 10 during the injection of the plastic material into the connecting channel. The connecting parts 12, 14 further comprise outer connecting parts 22, 24 which are adapted to mechanically keep the rudder parts truly connected, which is particularly important before the injection of the plastic material into the connecting channel.

The outer connecting parts 22, 24 cooperate in that the part 24 has a design, for instance a beveled bevel, which fits with the design of the part 22, which means that the part 24 can be snapped by the part 22 and thereby mechanically keep the rudder parts connected.

According to one embodiment, the inner connecting parts 16, 18 have contact surfaces 26, 28 between the connecting parts on the respective pipe part. The contact surfaces comprise a first contact surface 26 and a second contact surface 28. As can be seen from Figures 2 and 3, one of the inner connecting parts 18 is designed so that it constitutes at least partly a screening wall for the channel 10 while the other of the inner connecting parts 16 essentially constitutes the screening wall ar water mat the air duct. The connecting parts 16 and 18 thus form a joint because they are wrapped around and the contact surfaces are designed such that at a pressure increase in the connecting channel the first contact surface 26 is pressed against the second contact surface 28. In the embodiment shown in figure 2 the contact surfaces 26, 28 beveled, while in the embodiment shown in Figure 3, each of the contact surfaces has a step-like design that fits into each other. The figure shows a variant below one "step", but it is of course possible to have several steps.

The contact surfaces may have other shapes, for example combinations of the embodiments shown in Figures 2 and 3, provided that they are designed so that they absorb a pressure increase from the interconnection channel without affecting the interconnection surface 20, i.e. that this surface remains smooth.

For all designs, it is important that the contact surfaces must be designed so that it is possible to insert one contact surface into the channel part.

The outer connecting parts 22, 24 comprise one or more fixing parts 30, 32 adapted to keep the rudder parts fixed to each other, by applying a fixing force to said fixing parts, during the injection of the plastic material into the connecting channel. In more detail, the fixing members 30, 32 have partially radially oriented paths with respect to a cross section of the air duct tube. These radially oriented pads form an abutment surface for said fixing force which is supported, for example, by a surrounding mold which is used when the plastic material is to be injected into the channel 10.

There are various ways to ensure that the plastic material completely fills the channel. According to one embodiment, one or more pressure sensors can be arranged which give an acknowledgment that the duct is filled if the pressure exceeds a predetermined threshold value.

According to another embodiment, which is illustrated in Figures 2 and 3, one or more small openings 35 are arranged in the connecting part 12 so that there is a connection to the channel. When the channel 10 is filled, plastic material appears in the opening 35, which then gives an acknowledgment that the channel is filled.

The two parts can be of different sizes, as can be seen from Figure 1. For example, it may be advantageous to let one of the parts comprise the metal parts of the rudder, where any metal parts, for example annular reinforcing rings, can be laid into the cavity (mold) and cast in connection with the injection molding.

In addition, the type of connection where injection takes place allows that it is possible to fix, for example, metal parts with the same technology, for example to fix a metal post near the entrance opening. Figure 1 shows such a metal post near one of the openings 3.

Details on the inside of the finished product, such as support struts, and guide rails for controlling the air flow can also be inserted and integrated directly in connection with the injection molding, which reduces the need to assemble details afterwards, which in turn reduces manufacturing costs.

Figure 1 also shows some details on the outside of the pipe which have been integrated in connection with the injection molding of one of the pipe parts 4.

In order to enable fixing of metal components, for example studs, for example, this can be done by the connecting channel being connected to surfaces adjacent to these metal components so that plastic which is injected into the channel also reaches the metal components and fastens them.

The plastic material used is a suitable thermoplastic, preferably polypropylene or a polyamide, which is adapted to meet the half-strength requirements and temperature requirements set on the air duct. Normally the rudder must withstand the temperature in the range -40 up to +90 ° C, but in special cases breathe up to 150 ° C.

As mentioned above, the injection molding is preferably done by a hot channel injection molding technique, which will be briefly described below.

A hot runner system comprises a number of heated components which are used in injection molding of plastics where narrow plastic is injected into the cavities of the mold. The cavities thus have the same shape as the parts to be manufactured.

According to an embodiment of the present invention, there are three molds, one mold for each of the pipe parts (if two pipe parts are used), and one mold for the composite air duct pipe used when the duct is filled.

There are also so-called cold channel forming which is a simpler technique where a channel is formed between the two halves of the mold to feed plastic from the injection molding nozzle to the cavities. Each time the mold is opened to take out the molded parts, the material in the channel between the halves will also follow, resulting in waste of plastic material.

A hot channel forming system usually includes a heated rudder syringe and a number of heated nozzles. The main task of the rudder system is to distribute the plastic to the different nozzles that can be controlled so that a precisely determined amount of plastic can be discharged into the cavities in a number of injection points, where for example one or more needle valves are arranged and which needle valves are carefully controlled so that a correct amount of plastic material is sprayed. in.

Hot duct shaping often means that the mold becomes more expensive to manufacture and use, but allows savings in that there is less waste of plastic and that cycle times are reduced.

The present invention also relates to a method of manufacturing an air duct pipe for an internal combustion engine, especially for a motor vehicle.

The method will now be described with reference to the flow chart in Figure 4.

The method comprises: A - manufacturing at least two tube parts of a plastic material by injection molding; B - interconnecting said pipe parts along an interconnection line which is constituted by an interconnection duct formed by interconnecting parts for the respective pipe part in the area of the interconnection line, so that the pipe parts form said air duct members. on the inside of the air duct pipe, and that said connecting parts comprise outer connecting parts which are adapted to mechanically keep the pipe parts connected.

The method further comprises: C - keeping the rudder parts mechanically connected to said outer connecting parts; D1 - creating a tat joint between the rudder parts by injecting said plastic material into said interconnection channel; D2 - absorb pressure, with said inner interconnecting parts, from the interconnecting duct during the injection of said plastic material into the interconnecting duct.

According to one embodiment, the method also comprises the step of: D3 - enabling fixing of metal components, for example studs, in that the interconnection channel, named in D2, is connected to surfaces adjacent to studs.

It is referred to the above description of the connecting parts, and in particular to the description of the various details and function of the inner and outer connecting parts.

The plastic material consists of a suitable thermoplastic, preferably polypropylene or a polyamide.

According to the invention, steps A-D2, and preferably steps A-D3, are performed in a continuous procedure with a maximum duration of 200 seconds. More in 537 216 detail, the filling time of the rudder parts is of the order of 5 seconds, and these are manufactured simultaneously. The filling time of the interconnection channel is approximately 2-3 seconds. Other time is required for the parts to cool and for mechanically joining the pipe parts together and moving them over to the shape of the air duct pipe.

As mentioned above, the injection molding is done with a hot channel injection molding technique.

The invention also includes a computer program product comprising computer program instructions configured to perform the steps of the method described above when the computer program instructions run on a computer system, and where the computer program product is readable by a computer. In more detail, the computer program instructions control, for example, the times for injecting the plastic material into the molds and into the duct.

The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents can be used. The above embodiments are, therefore, not to be construed as limiting the scope of the invention as defined by the appended claims. 11

Claims (13)

537 216 Patent claims An air duct pipe (2) for an internal combustion engine, in particular a motor vehicle, consisting of at least two pipe parts (4, 6) which are made of a plastic material by injection molding and which are connected to each other along an interconnection line (8) which consists of a interconnection channel (10) formed by interconnection parts (12, 14) for respective rudder part in the area of the interconnection line (8), and all rudder parts (4, 6) are connected to each other and joined to each other by injecting said plastic material into said interconnection channel (10 ), characterized in that said connecting parts (12, 14) comprise internal connecting parts (16, 18) which are shaped so as to form a smooth connecting surface (20) on the inside of the air duct tube (2) and which are adapted to receive the pressure of the connecting duct ( 10) during the injection of said plastic material into the interconnection channel, and that said interconnection parts (12, 14) comprise external interconnection parts (22, 24) which are are adapted to mechanically keep the rudder parts interconnected, said outer connecting parts (22, 24) comprising one or more fixing parts (30, 32) fitting all the Walla rudder parts fixed to each other, by applying a fixing force to said fixing parts, during the injection of the plastic material into the connecting duct, and wherein said fixing parts (30, 32) have partially radially oriented portions with respect to a cross-section of the air duct tube, these radially oriented portions forming abutment surface for said fixing force. The air duct pipe according to claim 1, wherein said inner connecting parts have contact surfaces (26, 28) between the connecting parts on the respective pipe part, and that the contact surfaces comprise a first contact surface (26) and a second contact surface (28) and the contact surfaces are so shaped that in a pressure boiling in the interconnection duct, the first contact surface (26) is pressed against the second contact surface (28). 12 537 216 The air duct tube according to claim 2, wherein said contact surfaces (26, 28) are inclined. The air duct pipe according to any one of the preceding claims, wherein the injection molding takes place with a hot duct injection molding technique. The air duct tube according to any one of the preceding claims, wherein said plastic material is a thermoplastic, preferably polypropylene or a polyamide. A method of manufacturing an air duct for an internal combustion engine, in particular for a motor vehicle, the method comprising: A - manufacturing at least two tube parts of a plastic material by injection molding; B - interconnecting said rudder parts along an interconnection line formed by an interconnecting duct formed by interconnecting parts for each rudder part in the area of the interconnecting line, so that the rudder parts form said air duct rudder. on the inside of the air duct, and said coupling parts comprise outer connecting parts adapted to mechanically keep the rudder parts interconnected, said outer connecting parts (22, 24) comprising one or more fixing parts (30, 32) adapted to keep the rudder parts fixed to each other, by aft. applying a fixing force to said fixing parts, during the injection of the plastic material into the connecting channel, and said fixing parts (30, 32) having partially radially oriented portions with respect to a cross-section of the air duct tube, these radially oriented pads form the abutment surface of said fixing force, and the method further comprises: C - keeping the rudder parts mechanically connected to said outer connecting parts; D1 - creating a tat joint between the rudder parts by injecting said plastic material into said interconnection channel; D2 - absorb pressure, with said inner interconnecting parts, from the interconnecting duct during the injection of said plastic material into the interconnecting duct. The method according to claim 6, wherein the method comprises: D3 - enabling fixing of metal components, for example studs, in that the interconnection channel, mentioned in D2, is connected to surfaces in connection with said metal components. The method according to claim 6 or 7, wherein said inner connecting parts have contact surfaces between the connecting parts on the respective pipe part, and that the contact surfaces comprise a first contact surface and a second contact surface and that the contact surfaces are so shaped that during a pressure increase in the connecting channel the first contact surface (26 ) against the second contact surface (28). The method of claim 8, wherein said contact surfaces are beveled. The method according to any one of claims 6-9, wherein the injection molding is performed with a hot channel injection molding technique. The method of any of claims 6-10, wherein said plastic material is a thermoplastic, preferably polypropylene or a polyamide. The method according to any one of claims 6-11, wherein steps A-D2 are performed in a continuous procedure with a maximum duration of 200 seconds. A computer program product comprising computer program instructions configured to perform the steps of the method according to any of claims 6-12, when the computer program instructions {cars on a computer system, the computer program product being readable by a computer. 537 216 1/2 2 \ I